Offshore oil and gas operations typically involve drilling a wellbore through a subsea formation and disposing a wellhead at the upper end of the well (e.g., at the mudline). A string of casing can be landed in the wellhead, and a tubing spool is generally connected to the top of the wellhead. A tubing hanger lands in the tubing spool, and the tubing hanger suspends a production tubing string through the wellhead and tubing spool into the casing string. A conventional production tree can be connected to the top of the tubing spool to route product from the tubing hanger (and production tubing) toward a production riser. The production riser generally includes a series of riser pipes connected end to end to connect the subsea production components to, for example, a topside production facility. Such subsea systems are often used to extract production fluids from subsea reservoirs.
Recently, the oil and gas industry has begun to see increased activity and interest in developing a wider variety of offshore reservoirs. Specifically, there is an increased interest in developing high pressure high temperature (HPHT) subsea reservoirs. The term HPHT refers to wells that have mudline pressures in excess of 15,000 psi, temperatures in excess of 350 degrees F., or both. In an effort to develop such HPHT reservoirs, it is desirable to provide new methods and equipment to safely drill, complete, produce, and intervene on HPHT wells over the economic life of the well.